The present invention relates generally to a clamp and, more particularly, to a fluid powered, sealed pin locating and clamping apparatus.
Powered clamps have been commonly used to secure workpieces, such as sheet metal automotive body panels, polymeric parts and the like in checking fixtures, gauging stations, welding station, punching stations and other locations within a manufacturing environment. Many existing clamps are powered by hydraulic or pneumatic fluid pressure. For example, reference should be made to the following U.S. Patents, which have been invented by Sawdon: U.S. Pat. No. 6,502,880 entitled “Pin Part Locator” which issued on Jan. 7, 2003; U.S. Pat. No. 6,378,855 entitled “Locking Pin Clamp” which issued on Apr. 30, 2002; U.S. Pat. No. 5,190,330 entitled “Powered Clamp with Parallel Jaws” which issued on Mar. 2, 1993; all of which are incorporated by reference herein.
It is desirable to prevent a clamping arm from opening and releasing the workpiece if there is a loss of fluid pressure. Prior constructions employing such a feature are disclosed in U.S. Pat. No. 5,871,250 entitled “Sealed Straight Line Gripper” which issued to Sawdon on Feb. 16, 1999 and U.S. Pat. No. 5,853,211 entitled “Universal Gripper” which issued to Sawdon et al. on Dec. 29, 1998. These patents are also incorporated by reference herein.
In accordance with the present invention, a sealed pin locating and clamping apparatus includes a body, an actuator moveably supported by the body, a pin mounted to the body and a clamping member drivingly coupled to the actuator. The actuator includes a first rod having an internal cavity and a second rod rotatably positioned within the internal cavity. A portion of the pin is positioned within a cam slot formed in the second rod. The clamping member is drivingly coupled to the actuator such that the second rod rotates in response to linear movement of the first rod to position the clamping member.
The sealed pin locating and clamping apparatus of the present invention is highly advantageous over traditional clamps in that the clamp includes a clamping member contained within a precise slot of a locating pin. The clamping member is moveable in response to the application of pressurized fluid to a sealed chamber. This design eliminates exposing the inner mechanism to contamination such as weld flash, metal shavings or coatings on the metal which may rub off when parts are loaded over the pin locator clamp. Additionally, the clamping member is rotatable from a position inside the pin to a position outside the pin such that the workpiece may be freely positioned over the pin when the clamping member is retracted and firmly held in place when the clamping member is extended.
In addition, the present invention optionally includes a self-locking mechanism which does not allow the clamping mechanism to retract if fluid actuation pressure is lost.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.